Composition of matter adapted for increasing the water-resistance of fibrous substances specifically paper products and process of making same



Patented Nov. 23, 1937 UNITED. STATES PATENT OFFICE COMPOSITION OF MATTER ADAPTED FOR 3 INCREASING THE WATER-RESISTANCE OF FIBROUS SUBSTANCES SPECIFICALLY PAPER PRODUCTS AND PROCESS OF MAKING SAME mesne' assignments,

to Ellis-Foster Company;

Montclair, N. 1., a corporation of New Jersey No Drawing. Application November 22, 1929,

7 Serial No. 409,1

3 Claims. (01. 134-22) This invention relates to a composition of matter and to the process of making same and relates especially to a composition adapted for water-proofing various fibrous substances and in 5 particular paper material of various kinds.

This application has derivation in my copending applications Serial Numbers 29,258, 101,580, 106,575, 107,461, 286,485 and 394,141 which have matured into Patents Numbers and 1,899,086, respectively. I

The stock from which the paper product of the present invention is derived may be any suitable wood or rag pulp, fibre and the like, such as sulphite pulp, sulphate pulp, ground wood, rag stock and so forth and suitable mixtures of these.

The consistent petroleum hydrocarbons used in augmenting the water resistance of the paper product are preferably of a soft unctuous character such as may be produced, for example, by incorporating paraflin or ceresin wax with various proportions of petroleum oil. In Serial No.

101,580 I have proposed the employment preferentially of a water-white grade of medicinal petroleum oil such, for example, as Marcol. An

oil of this character may be incorporated with a light colored wax to make a consistent mass which when incorporated in paper pulp adds considerably to the waterproofing qualities, tends to 80 improve the texture and also enhances the flexibility so that the paper may be drawn more readily through dyes when a treatment of this kind is required. Various proportions of oil and wax may be used and, as stated in Serial Number '35 101,580, .a. proportion of one part of wax to two parts of oil, for example, may be employed. A

composition of wax and oil in this proportion yields an unctuous material of ointment-like quality somewhat similar to petrolatum. When 40 a wax of a thoroughly. amorphous character, such asceresin, is used the resulting unctuous body has a texture somewhat smoother than when paraifln wax is used.

In the several applications mentioned I have referred to the employment of wax of different kinds and in the present application I may use these same or kindred waxes as desired but preferably employ mineral waxes .such as paraiiin, ceresin and Montanwax. Th'ese solid petroleum hydrocabons incorporated with a proportion of a petroleum oil somewhat greater than the amount of wax yield as indicated unctuous bodies of varying degrees of hardness or softness. This 55 invention, therefore, comprehends petroleum wax softened with petroleum oil to such a degree as will form substantially an unctuous mass.

- In the manufacture of paper of various grades, but particularly those light in color, I prefer to employ refined waxes and oils free from any high degree of coloring matter which if present would tend to discolor the paper and depreciate its market value. However, I do not limit myselfto the use of medicinal grades of petroleum oil such as Nujol or Marcol but may employ various other liquid petroleum hydrocarbons such as those of a lubricating oil type, spindleoil, and the like.

Inmany cases paper substantially free from odor is required and the use of oils of low grade possessing considerable odor is undesirable. For papers which are required substantially free from odor I therefore employ a deodorized petroleum oil. f

In Serial 101,580 I have set forth the utility of hydrocellulose in paper pulp employed with wax or wax and oil waterproofing material and in the present invention I may likewise employ hydrocellulose to any desired degree.

The consistent petroleum hydrocarbon mixture preferably is introduced into the paper pulp as a dispersion or emulsion. Such dispersions may be prepared in various ways as, for example, by

dissolving one or two ounces of ordinary soap in a gallon of water and mixing this with the unctuous hydrocarbon mixture, the latter preferably being heated slightly above its melting point. Equal proportions by volume of the soap solution andthe unctuous material in admixture are passed through a colloid mill or other suitable dispersing or emulsifying device to yield a dispersion which-may be diluted with wateras required for addition to the paper pulp.

1 Thedispersion may be added to the pulp in the beater engine at any stage of the operation of heating, but preferably is introduced when the beating has been substantially completed. or the or at the screens. Hence at some stage prior to the formation of the paper pulp into a sheet the dispersion isadded in an amount sufiicient to have present in the dried pulp stock a quantity of the unctuous waterproofing agent, say from two to five per cent on the dry weight of the paper. This range, however, does not place any dispersion may be introduced into the Jordans' -ticles.

waterproofing agent, before incorporating with the pulp at any suitable stage, may be treated with alum, calcium chloride, hydrochloric or sulphuric acid, or any other agent reactive with soap to alter the hydrogen ion value of the dispersion in order to make it conform in any suitable way with the pH value of the pulp. In other cases the dispersion maycontain sodium silicate and a precipitant such as alum may be added to the dispersion prior to incorporation with the pulp in order to pre-set the unctuous hydrocarbon par- Again, the dispersion may be added to the beater or elsewhere without such preliminary neutralization, precipitation or similar treatment and the setting of the unctuous particles brought about in the presence of the pulp by the addition of alum or other precipitant.

In producing paper in this manner the employment of rosin size and the like is not precluded, although not ordinarily recommended from the standpoint of increased water resistance as the disseminated unctuous particles throughout the paper structure may be expected to produce in the paper an adequate degree of waterproofing or resistance to water penetration without the presence of the usual paper sizing and at a cost ordinarily lower than can be secured by the use of rosin size.

The paper pulp having been treated in this manner is run onto the usual paper-making machine to produce paper, board and similar products. It may be hot calendered if desired to further impregnate and disseminate the unctuous mass throughthe paper tissues. Heavier paper or board may be built up in layers, in which case it will be found feasible to apply the unctuous waterproofing dispersion to one or more layers only, .if desired, in order to reduce the amount of the unctuous material present with consequent saving in cost. Water then may penetrate through those layers which are not so treated but will not pass readily through the layer or layers treated with the unctuous waterprooiing dispersion.

In Serial Number 101,580, I have referred to the employment with various waxes, such as parafiln, ceresin, Montan, carnauba, japan, beeswax, and the like, alone or admixed with rosin, various oils and so forth, of additions of starches.

I may employ with the present wax-containing emulsified as, for example, by forming a disa,

V A very. high degree of dispersion maybe obtained-in this persion with the aid of a colloid mill.

manner.

The sizing compositions prepared .in accordance with the presentinventioiir may also be employed with sizing compositions that contain oxidized hydrocarbons and particularly oxidized waxes. As examples of oxidized hydrocarbons and waxes that may be utilized, there may be mentioned parafiin wax, and other waxes such I as carnauba, candelilla, Montan, ceresin, and the like. Blown hydrocarbons, such as blown petroleum oils, may also be utilized, and mixtures of the blow'n waxes with oils, or of the blown waxes with blown oils, or of waxes with blown oils,

. and any combination of these ingredients may be employed in connection with the present invention. The waxes may be oxidized andpthen incorporated with oils to soften the waxes, or the waxes and oils may be simultaneously submitted to an oxidation to produce the desired products. In the preferred instance, whatever oxidized hydrocarbons are employed should be of substantially non-pigmenting power, so that the paper will not be substantially discolored. In such instances, therefore, substances such as blown tars, blown asphalts, and the like, which would be of a contaminating character and which would be dark in color and would accordingly discolor the paper, are avoided. However, in those cases where discoloration or dark coloration is of relatively minor importance, such darkened oxidized materials may be utilized. As stated; however, the preferred instances involve the employment of oxidized hydrocarbons which are substantially light in color, and free or substantially free from undesirable odor, and which do not impart any objectionable taste to any food material when the paper is used in contact therewith. For example, where the oxidation of parafiin wax is carried to a stage where dark colored resinous substances or strongly odoriferous aldehydes and the like result, these when present in paper used in packing foodstuffs may exert a contaminating influence. For such purposes, therefore, it is preferred to keep the oxidation within that range where resinous substances substantially are not formed, and the physical appearance of the wax which has been subjected to incipient oxidation is only very slightly altered.

,As an example of an oxidized wax that may be employed, oxidized paraffin may be prepared by blowing a current of air or oxygen, or other oxygen-containing gases, through the molten material for a period of several hours, the temperature usually ranging from 160200 C. Oxygen goes into combination and to a certain extent fatty acids are formed together with various other. oxygenated products. For the purposes of the present invention, it is preferred to carryand permit it to disperse more readily in an aque-- ous. medium. By blowing wax for several hours at a temperature of 160 C. but stopping the operation before deep-seated changes take place, a product which has been thus subjected to incipient oxidation results which is desirably employed 9 in carrying out the purposes of the present invention.

The blown wax in a stage of incipient oxidation is mixed with pulp, preferably in the beater engine, or any other suitable stage in advance.

of actual formation into a sheet. Two or three per cent by weight of the blown wax, based on the paper material, may be introduced advantageously in this manner. Wax in this proportion, or even lesser relative amount creates a desirable waterproofing effect. The paper stock may be any ordinary paper stock, such as is illustrated above.

Difliculty has arisen in the past in the endeavor to use paraflin wax in paper pulp due to clogging of the felts and screens with wax. In the present invention, it is proposed to oxidize the wax to a stage sufiicient to render its dispersion in water very thorough and. permit of more effective occlusion of the dispersed blown wax 'by the wet paper pulp. The exact degree of wa-' terprooflng or water resistance created depends sizing" composition into the pulp in rosin size or other paper sizing agent. Alum,

aluminum hydrate, and various other coagulating agents for size may be used, as required. If the coagulating agents are used together with'the sizing material prior to the incorporation of the the beater, a preset sizing agent will result. Such preset compositions ofier advantages, but 'on the other hand, the'sizing compositions may be employed in the usual manner with the coagulating agents added after the sizing composition has been incorporated into the pulp.

Instead of'using the harder and more expensive grades of paraffin wax, it is possible to use various cheaper gradesof wax including scale wax, or wax which has been softened with various oils. Thus in some instances it is preferred to employ the emulsion or dispersion of a mixture of wax in a good grade of petroleum oil, such mixture having been air-blown to at least a state of incipient oxidation. For a very high grade of paper there may be employed a blown mixture of wax and one of the so-called medicinal petroleum 'oils, in which products oil such as"Nujo l or Marcol are typical. For lower grades of paper, especially when color is not important, various petroleum oils admixed with wax may be blown to yield an oxidized product which when dispersed in an aqueous medium may be readily incorporated in the wet paper pulp.

. The waxes themselves may be blown or mixtures of the waxes, or mixtures of waxes with oils, may be oxidized simultaneously. For example, a mixture of waxes may be simultaneously oxidized oxidized waxy material. Thus paraffin wax with 5 to 10 per cent of Montan wax may be blown with air at a temperature of say, 170 C. for five hours. In like manner, blown mixtures of paraffin wax, petroleum oil and Montari wax or other wax of a character different from paraffin wax may be blown and thus oxidized. Thus blown ceresin or unctuous mixtures of a petroleum wax such as ceresin with a petroleum oil may be utilized.

The dispersion of the oxidized material may be made in various ways, preferably with the aid of one or more emulsifying agents such as soap, alkali, starch, bentonite, silicate of soda, and the like. Thus a few per cent of stearic or oleic acid may be melted with the oxidized parafiin and the mixture passed through an emulsifying apparatus such as a colloid mill. Using a colloid mill,

the amount of dispersing agent may be' quite small. This is advantageous when ordinary soaps are employed because these tend to produce foaming in the beater and therefore the proportion of these should be kept at a minimum.

Less than 1 per cent of potassium or sodium' oleate may be employed to make a satisfactory dispersion of oxidized paraffin wax in water.

' The dispersion may contain about 50 per cent of wax and yet be readily handled.

As indicated above, the oxidized parafiln emulsion may be added to the beater engine which advantageously may be done at the time the paper stock is charged thereinto. After thorough mixing in the usual manner in the beater a quantity of rosin size or any other desired sizing agent may be added andsuch size set in the usual manner with alum or with any other setting agent. The addition of rosin size or similar sizing agent is, however, not necessary in making various forms of paper, it being proposed to produce paper without a sizing agent of a resinous character, if so desired, employing solely the oxidized material aforesaid to create'adequate water resistance for the purpose in hand.

A paper pulp which contains a substantial proportion of hydrocellulose is advantageous in assisting in the fixation of the oxidized wax. The hydrocellulose may be added to the pulp or formed in it in any suitable manner.

The invention may be illustrated by the following:

A mixture of equal parts by weight of sulphite pulp and ground wood is agitated in water in the beater with a dispersion of dxidized paramn wax sufficient to introduce about 4 per cent of wax into the finished paper.. The dispersion of the blown wax is made by violent agitation of equal volumes of the wax and a 1 per cent solution of sodium or potassium oleate. Agitation in the beater is continued until hydrocellulose is formed to a considerable extent. After thorough admixture in this manner rosin size is added sufficient to introduce 1 or 2 per cent of rosin or resinate andthis rosin size is set by alum, either already present inthe beater, or added after the rosin size has been incorporated. The proportion of alum introduced is suificient to react both with the alkali of the rosin size and with that of the sodium or potassium oleate employed in dispersing the blown wax.

The pulp so treated is formed into a sheet of paper which may be of single layer construction .or may be built up in the paper machine in several layers to form a board. Whether made in single sheet or single layer form, or built up in a plurality of layers, I include under the designation paper these and other varied forms of sheeted paper pulp. 1

The sheet is then calendered, preferably hot, and the particles of oxidized wax, oxidized oil, and so forth, are thus further disseminated through the fibrous mass 7 thereof) composing the sheet. In this way an enhanced degree of water resistance is obtained.

The procedure of the foregoing illustration may be varied in different ways, as for example, a cheaper paper stock may be made by utilizing 3 parts by weight of ground wood'to 1 part of sulphite or sulphate pulp. The oxidized waterproofing material may be a blown mixture of paraffin wax containing 10 to 20 per cent of hydrocarbon oil. The employment of the blown hydrocarbon oil may be desirable in operations where the paper is to be printed. In other words, the illustration set forth depicts merelyone procedure and sincenumerous variations are possible, it is to be understood that the invention is not restricted in any manner by the specific character of the illustration.

In the illustration set forth above 4 per cent of vantageously in such cases.

the oxidized waxy material is recommended. This is a high proportion for many purposes and 1 or 2 per cent of the blown material may be used ad- On the other hand, for making waxed paper and'using blown wax, I may increase the proportion to produce the desired waxed effect.

It should be understood that I am not precluded from adding unoxidized oils and waxes to the blown Wax or blown mixtures of hydrocarbons, when for any reason such admixture is desired, as for example, to cheapen the product.

Reference has been made above to the desirability of adjusting the hydrogen ion value of the dispersion in order to make it conform in any suitable way with the pH value of the pulp. It is preferred to employ a pulp which has been brought substantially on the acid side, that is one having a pH value of less than 7 but not substantially less than 1.5, since too great an acidity is harmful since it is apt to break down .the emulsion and cause coagulation of the colloidally dis persed wax particles, whereby proper absorption does not occur. The particular hydrogen ion conand a hydrocarbon oil.

oentration of the pulp varies for diiferent conditions and stocks being treated. A preferred range of hydrogen ion concentration of the stocks when wax sizing compositions are employed may be stated to lie between 7.2 to 5.5. With ordinary rosin sizes, the pH of the stock is preferably maintained within the limit of 4.5 and 5.0. The utilization of wax dispersions, therefore, enables a stock to be employed in which the hydrogen ion value is not as critical as when the ordinary rosin sizes are employed. Accordingly, depending onthe particular hydrogen ion concentration of the stock employed, the dispersion or emulsion may have its pH value altered to conform in any suitable way with the pH value of the pulp.

Having thus set forth my invention, I claim:

1. A paper sizing composition comprising a blown mixture of wax and petroleum oil.

2. A paper sizing composition comprising a blown wax softened with an oil.

3. A paper sizing composition comprising an aqueous emulsion of an oxidized petroleum wax CARLETON ELLIS. 

